Products of the F factor transfer operon are being analyzed. We are examining the amount of "protein S" (product of traT) present in the outer membrane of male cells as a measure of tra operon expression under various conditions of growth. We are examining one and two dimensional gels of cell extracts and membrane preparations from male and mutant male strains in order to identify F tra operon products and intermediates in F pilin biosynthesis. We have also been examining the protein products of the kanamycin transposon Tn903.